Morse theory and gravitational microlensing


Journal Article

Morse theory is used to rigorously obtain counting formulas and lower bounds for the total number of images of a background point source, not on a caustic, undergoing lensing by a single-plane microlens system having compact bodies plus either subcritical or supercritical continuously distributed matter. An image-counting formula is also found for the case when external shear is added. In addition, it is proven that a microlens system consisting of k lens planes will generate N = 2M- + Πi=1k(1 - gi) images of a background point source not on a caustic, where M- is the total number of critical points of odd index of the time-delay map and gi is the number of stars on the ith lens plane. Morse theoretic tools also yield that the smallest value N can have is Πi=1k(1 + gi). © 1992 American Institute of Physics.

Full Text

Duke Authors

Cited Authors

  • Petters, AO

Published Date

  • January 1, 1992

Published In

Volume / Issue

  • 33 / 5

Start / End Page

  • 1915 - 1931

International Standard Serial Number (ISSN)

  • 0022-2488

Digital Object Identifier (DOI)

  • 10.1063/1.529667

Citation Source

  • Scopus